1. Technical Field
The disclosure relates to an image processing apparatus which converts color image data to mono chrome image data and an image forming apparatus including the same.
2. Related Art
Japanese Unexamined Patent Application Publication No. Hei 10-63833 proposes a technique of printing and outputting inputted color image data as a monochrome image by converting the color image data to monochrome image data. In this technique, since simple monochrome conversion results in a decrease in the amount of information of the image data, the proposed technique involves the following expansion processing to improve the visibility of the monochrome image. Specifically, the color image data of each of RGB colors is first subjected to the expansion processing of expanding each pixel region including pixel values equal to or larger than a certain value, and then the resultant color image data is converted into the monochrome image data.
In the expansion processing, for each of the colors of RGB, the pixel region including the pixel values equal to or larger than the certain value is expanded to neighboring pixels around the pixel region by assigning pixel values equal to or larger than the certain value to the neighboring pixels.